The present invention relates to a cooking utensil which includes a gas sensor for automatic cooking control purposes.
A microwave oven is proposed in my copending application Ser. No. 71,179, "COOKING UTENSIL CONTROLLED BY GAS SENSOR OUTPUT", filed on Aug. 31, 1979, wherein a gas sensor is disposed in an exhaustion duct for detecting a gas concentration developed from an oven cavity. When the gas concentration reaches a preselected value, the gas sensor output shows a preselected value, and in response thereto the microwave generation is terminated.
Since the gas sensor is also effective to detect the gas leakage, it is desirable to make such a microwave oven operate as a gas leak alarm when the microwave oven does not perform the cooking operation. However, the system must be constructed so that an ambience gas is properly introduced near the gas sensor while the microwave oven does not perform the cooking operation.
Accordingly, an object of the present invention is to provide a combination of a gas sensor output controlled cooking utensil and a gas leak alarm.
Another object of the present invention is to provide a control circuit for making a cooking utensil employing a gas sensor to operate as a gas leak alarm when the cooking utensil does not perform an actual cooking operation.
Still another object of the present invention is to provide a gas leak alarm system incorporated in a microwave oven which includes a gas sensor for automatic cooking control purposes.
Other objects and further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. It should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
To achieve the above objects, pursuant to an embodiment of the present invention, a gas sensor is disposed in a path of the gas exhausted from an oven cavity. A control circuit is provided for terminating the microwave generation when an output voltage signal of the gas sensor reaches a preselected value.
A blower fan system is provided for introducing fresh air into the oven cavity and for developing the exhaust gas from the oven cavity while the microwave oven performs the actual cooking operation. When the microwave oven does not perform the actual cooking operation, the gas sensor control system is continuously supplied with power for gas leakage detection purposes, and the blower fan system is intermittently activated to intermittently introduce the ambience air toward the gas sensor for gas leakage detection purposes. The intermittent activation of the blower fan system ensures an accurate detection operation of the gas sensor, and minimizes the power consumption.